## Why does every address look so different from every other address? Look at the list of addresses in your Sparrow wallet again. Can you see any pattern between one address and any other address? Or do they look completely unrelated to each other? If you think they are unrelated, you are correct. If you want to understand why the addresses are unrelated to each other, then you first must understand hashing. When a computer hashes information (input), it produces another piece of information called a "hash". A hash has some interesting qualities: * A hash is unique to its input Do you keep a copy of your resume on your computer? If we "hashed" your resume file using a hashing program called `sha256sum`, you would see a long string of characters, like this: `7af0647fdc5a0a70840c9b71742c573e39990dde9e1dcd73479c4ca4aa38d74d`. Your resume (unchanged) will always produce the same hash. No other file on your computer (or any file in the world) will produce that same hash. What would happen when you update your resume? The information in the file has changed, so it would produce a new hash. * A hash is random What if you corrected just a small spelling error on your resume and hashed it again? You would get a completely different hash, like this: `821ae29478809a6cb40d17810e0b5304c8c9c334035f3633337d3044fe932a81`. The tiniest change to the input will result in a wildly different hash. * A hash is small Much like a fingerprint is a small piece of information that identifies you, the hash is a very small piece of information that uniquely identifies the input that you gave it. Your resume probably contains hundreds of words that describe your education and career paths. But your resume's hash is less than 100 letters and numbers. * A hash does not describe any information about the input A fingerprint is unique to you, but it doesn't describe a lot about you. If someone had a picture of your fingerprint, they do not know where you currently are or what you had for breakfast or what you will say or do in the future. The fingerprint doesn't tell them much, except what your fingertip looks like, if it were covered in ink. A hash tells even less than a fingerprint does. It does not describe anything about its input. This means that a hash is "one-way". You can't "work backwards" from a hash to produce any of the original information. If you accidentally deleted your resume, but had your resume's hash, you are still out of luck -- you could not use the hash to recover any of the original information in the resume file.